Among the three ALDHs we examined, 16.8% (162/967) of CSF‐CTCs had detectable expression of ALDH1A. 27.7% (268/967) of CSF‐CTCs across five LUAD‐LM patients had CD44 expression, a stem cell marker for CTC aggregation and polyclonal metastases.46 Here, CD44 is linked to lymphangioma.